The present invention relates generally to integrated circuit part removal apparatus and methods, and more particularly to die removal apparatus and for use with semiconductor integrated circuit chips and components that are attached to high density multichip interconnect hybrid packages, and for removal of large area substrates from packages.
Spacings between integrated circuits are commonly between 0.100 and 0.250 of an inch, and high density multichip interconnect technology has reduced device spacing to a point that reworking of hybrids is now more difficult than ever. Spacing of high density multichip interconnect technology devices has decreased by as much as a factor of ten in the last few years. This has caused the abandonment of conventional rework techniques.
Conventional removal methods for use in removing large area devices, and removing closely spaced devices attached to substrates employ a well known "hot-shot" technique. This technique requires heat to be applied to the bottom of the substrate of the hybrid package, while applying a stream of hot inert gas onto the surface of the device to be removed. Then the device is peeled away from the substrate using a wedge shaped instrument. On delicate thin film multilayer substrates, large area devices, or closely spaced devices, this process is not feasible. Moreover, this technique is neither accurate nor repeatable.
Equipment has been developed that vertically removes devices from substrates by applying pure tensile force to a device. However, delicate high density multichip interconnect substrates are not able to survive this type of force alone. Also, no known equipment exists which is able to torsionally test flip-chip die attach shear strengths.
The transactions of the 1990 International Electronics Packaging Society (IEPS) includes a technical paper that surveys the field of removal of integrated circuits from multi-chip modules. The paper discusses die shear, dual blade twist off, tensile die pull, and hot gas/tweezer techniques of die removal. The paper appears at pages 77-89, and is entitled "A Review of Repairable Die Attach For CuPi MCM". The author is Thom A. Bishop of Microelectronics and Computer Technology Corp. (MCC), Austin, Tex. 78727.
Furthermore, there are times when it is necessary to remove a substrate from a package. These substrates are typically soldered or adhered to the large area substrates using adhesive epoxy or thermoplastic material and it has heretofore been difficult, if not impossible, to remove defective ones without destroying the complete substrate.
Accordingly, it would be desirable to provide for equipment that is capable of removing devices from high density multichip interconnect substrates, and remove substrates from a package without damage to other devices or substrates. It would also be desirable to provide for equipment that is able to torsionally test flip-chip die attach shear strengths.